Re: Black Generation Question
Re: Black Generation Question
- Subject: Re: Black Generation Question
- From: Henrik Holmegaard <email@hidden>
- Date: Sun, 4 Feb 2001 10:19:56 +0100
I guess the bottom line question is, how does black generation
visually affect the print? I would think that increasing it would
give deeper, more solid looking blacks, but not having time to
experiment, I'm only speculating.
Vice versa, the blackest black is the C100 M100 Y100 K100 patch and
not the K100 patch.
The black is always process dependent and you have to find out the
attributes of the printing mechanism and the printing process to
apply black correctly. Also each print profiling tool has it's own
black generation algorithms. You should get the same CIELab values
for different black generation using the same print profiler, though
(the simple way of putting it).
The black depends on the nature of the printing technology and the
print speed, for instance.
Inkjets take minutes to print a page proof and then some time for the
ink to dry. The elementary spot size is larger than on a press and so
you see black dots clearly. Therefore, use a very short UCR black as
in the Printopen preset or say the preset GCR in ProfileMaker 3X with
a low black start that keeps black dots out of the midtones and
highlights where black will be formed as CMY only. The choice of
approach depends on the cost of your CMYcm ink cannisters -:).
With presses you get other problems when magenta that has a big
effect on the graybalance overshoots a bit, hence you substitute K
for CMY throughtout the color space to guard against graybalance
problems and ensure very quick drying as less total ink is laid down.
This is the basis of GCR.
With dye subs you want to watch out for the heating elements. Don't
drive the total CMYK up to 400% on the DCP 9000 / DS 8650PS - 8670PS
as the elements will have more trouble cooling before a rapid color
transition than if you run a lower total CMYK of 360 - 370 with no
risk of artifacting.
--
Henrik Holmegaard
TechWrite, Denmark